General Psychology - Lecture 8

Retinal (binocular) disparity

Images produce different image on each retina

Greater disparity —> less depth

Convergence

Turning inward of eyes toward nearby object

Closer object —> greater convergence

Perceptual Constancy

Interpretation of changing sensation as perception that is relatively consistent

Color Constancy

Consistent perception of color of object although the amount of light changes

Lightness Constancy

Consistent perception of shade of objects although the amount of light changes

Shape Constancy

Perception that object’s shape remains constant despite changing shape of retinal image

Size Constancy

Perception that the size of objects remain constant despite different size of images on retina

Monocular Cues

Can use only 1 eye

Sensation

Process by which our sensory receptors and nervous system receive stimulus energies from our environment.

Perception

The process by which we interpret sensory information to form an understanding of our environment.

Transduction

The conversion of physical stimuli into neural signals by sensory receptors, allowing us to perceive the world.

Bottom-up Processing

The method of processing information that begins with sensory input, which is then integrated with prior knowledge to form perceptions.

Top-down Processing

The cognitive process where higher-level knowledge, expectations, and experiences influence the interpretation of sensory information.

Absolute Threshold

The minimum intensity of a stimulus that can be detected 50% of the time by an observer.

Difference Threshold/Just Noticeable Difference (JND)

The smallest difference in stimulus intensity between 2 stimuli that a person can detect

Weber’s Law (fraction)

The principle stating that the difference threshold is a constant proportion of the original stimulus intensity, indicating how much a stimulus must change for it to be noticed.

Sensory Adaptation

The process by which our sensitivity to a constant stimulus diminishes over time, leading to decreased response to unchanging stimuli.

Signal Detection Theory

A framework used to understand how individuals detect faint stimuli amidst noise; it incorporates decision-making processes, accounting for factors such as motivation and expectations.

Detection (perception of a stimulus) depends on

Sensitivity of sensory systems

Response bias

Response Bias

A systematic tendency to respond in a certain way regardless of the stimulus; influenced by factors like expectations and preferences in detection tasks.

Signal Detection

Possible outcomes:

Hits, misses, false alarms, correct rejections

Factors Affecting Response Bias

Expectations

Motivation

Perceptual Organization (Gestalt)

We perceive objects as whole rather than as a sum of the individual parts

Figure-ground perception

is the ability to separate the visual field into background and foreground elements, allowing us to identify and focus on specific objects.

Proximity

Is a principle of Gestalt psychology that states objects that are close to each other tend to be perceived as a group.

Similarity

Is a principle of Gestalt psychology that suggests objects that are similar in appearance are often perceived as belonging to the same group.

Continuity

Is a principle of Gestalt psychology stating that lines are perceived as following the smoothest path, and elements arranged in a continuous pattern are grouped together in our perception.

Closure

Is a principle of Gestalt psychology that refers to the tendency to perceive incomplete shapes or patterns as complete, filling in gaps mentally to create a whole.

Depth Perception

is the ability to perceive the world in three dimensions and judge distances, relying on various visual cues such as binocular disparity and motion parallax.